Presently, the quality of a manufactured recording disk is evaluated based on jitter occurring on a signal read from the recording disk. However, as the recording density of information recorded on the recording disk increases, the read signal is not only decreased in the S/N ratio of high frequency components but also becomes more susceptible to intersymbol interference. Therefore, a greater jitter than an intrinsic jitter is detected from the read signal acquired from the recording disk on which the information is recorded in high density. This results in a problem that the recording disk cannot be evaluated correctly.
The invention is directed to a solution to such a problem. An object of the invention is to provide a disk evaluation apparatus capable of performing a highly reliable disk evaluation even on the recording disk on which the information is recorded in high density.